For universal joints used nowadays in cardan shafts, transmission as free of play as possible is required between the universal joint sockets and the spider. For the compensation of production-related and installation-related play between the journal of the spider and the universal joint socket in the axial direction, it is known to press the universal joint socket under prestress against the journal of the spider.
The functioning and quality of a universal joint, which is also to be designated as a cardan joint, is assessed particularly in terms of the generation of noise, true running and oscillation behavior. For this purpose, the absence of axial play between the journal of the spider and the respective universal joint socket is critical. The axial play is determined, in particular, by a narrow tolerance of the dimension between the bottoms of two opposite universal joint sockets in relation to the end faces of the universal joint journals.
A generic universal joint is known from DE 21 20 569 A. The rolling bearing ball arranged centrically between the end face of the journal and the bottom of the universal joint socket is guided partially in a recess of the journal and in a further recess of the bottom of the universal joint socket. This set-up does not allow a play-free orientation of the journal with respect to the universal joint socket.
Publication DE 21 22 575 A, also known, shows a universal joint socket, in which only a relatively flat spring characteristic curve can be achieved because the universal joint socket has to be mounted under pressure force and has a bottom with a small wall thickness. This spring characteristic curve, combined with the projecting run-on surface directed toward the journal at the center of the bottom, initially fulfils the condition of play-free bearing contact. The pressure force has the disadvantageous effect of causing a vaulting of the run-on surface, with the result that the end face of the journal initially runs solely on the outermost edge of the run-on surface. After a run-in phase, that is to say after the vaulting has rubbed off, a planar run-on surface is established between the end face of the journal and the bottom. This is associated with a reduced pressure force which, in the unfavorable case, is not sufficient for compensating the axial play between the journal and the universal joint socket.